Bag pressure indicator for suction cleaners



I c. G. TRoxLR 2,244,130

June 3, 1941.

BAG PRESSURE INDICATOR Fon sucTIoN CLEANERS Filed lay 18, 1939 l l Q 0 oA /zaa-g l' fha/les 6'; Trax/el' Patented June 3, 1941" BAG PRESSUREINDICATOR FOR SUC'IION ANERS Charles G. Troxler, North Canton, Ohio,assigner to The Hoover Company, North Canton, Ohio, a.

corporation of Ohio Application May 18, 1939, Serial No. 274,368

4 Claims. (Cl. 'H6-65) This invention` relates to improvements in bagpressure indicators for suction cleaners and more particularly to anauxiliary suction-actuated device for rendering a bag pressure indicatorinoperative except under conditions for which the bag is directlyresponsible.

The necessity for an auxiliary locking device associated with a bagpressure indicator is due to the fact that under certain operatingconditionsof a suction cleaner, the indicator is likely to display afalse signal thereby indicating to the operator that the dirt bag shouldbe emptied, whereas the dirt bag may be quite free of dirt. For example,if a cleaner equipped with an indicator responsive'to the pressure atthe inlet end of the dirt bag is being operated on a carpet of averagequality and texture and is then wheeled onto a bare cor or a floorcovering that is quite thin 'and porous, the indicator is likely todisplay the bag emptying signal regardless of the condition of the bag.And the reason for this is that when the nozzle leaves the carpet, theseal is broken and the increased air-flow causes a drop in the suctionat the nozzle, accompanied by a corresponding increase in the pressureat the exhaust outlet because the bag is notrcapable of disposing of theincreased volume of air discharged by the fan and this increase inpressure is sufficient to cause the bag pressure indicator to functionas it would if the increasedvpressure were due to a clogged condition ofthebag.

Therefore, the object of the present invention is to provide alockingdevice which will prevent the indicating device from functioningfrom causes other than the dirty condition of the bag.

The particular type of indicator employed is not particularly important,although for convenience one disclosed in an application for a UnitedStates Letters Patent, bearing Serial No. 102,897, filed September 28,1936, has been reproduced herein. Thus, the cleaner and the indicatorper se will require only a brief description. In the accompanyingdrawing:

Figure i is a general view in side elevation of a suction cleanerequipped with a pressureresponsive bag pressure indicator and anauxiliary suction-responsive locking device associated therewith:

Figure 2 is an enlarged detail view in vertical section through the bagpressure indicator and associated locking device, showing the latter inits inoperative position; and

Figure 3 is a view similar to Figure 2, but showing the locking devicein locking engagement with the signal member of the bag pressureindicator.

Referring first to the general structure and arrangement of the cleaner,the same comprises a main casing I, having a nozzle portion 2 extendingtransversely across its forward end and supporting a centrally disposedmotor 3 enclosed within a dome-shaped cover 4 and having direct drivingconnection with a fan located within a fan chamber forming an integralpart of the casing l immediately below the motor. The fan chamber has arearwardly directed exhaust passage 5 terminating in a flanged outletconnection 5a to which a dirt bag 6 is removably attached;

The nozzle portion 2 includes a nozzle chamber defined in part by avertical rear wall 2a and having the usual downwardly opening suctionmouth communicating with the fan chamber through an inlet passage. Undernormal operating conditions a substantially uniform suction ismaintained within the nozzle chamber and a substantially uniformpressure within the discharge outlet passages, although as the baggradually becomes filled with dirt, a back pressure is built up whichresults in a drop in the nozzle suction and a reduction in the cleaningeffectiveness of the cleaner unless the bag is emptied.

Therefore, it is the increased back pressure due to a dirty condition ofthe bag that the indicator is intended to register by displaying avisual signal which can be seen by the operator.

The indicator is preferably located adjacent the rear end of the casingI and is supported upon the top wall Iathereof between the motor 3 andthe outlet passage 5 and concealed beneath the rear end portion of thecover 4.

Theindicator'consists primarily of a frame 1 having al verticallyarranged cylindrically cupshaped body portion 1a opening forwardly.Partially enclosed by this cup-shaped body portion is a bellows member 8consisting alsorof a cupshaped member of some flexible material such asrubber and having a series of corrugations throughout its length. 'Iheopen end of the bellows member is fitted around a shoulder at the baseof the body portion of the frame and at its free endA is formed abutton-like projection 8a.

Having hinged connection along its upper edge with the forward ends of apair of brackets 9 mounted on top of the frame 1 is a signal member l0secured to the outer end of the bellows member by the insertion of thebutton 8a through an opening therein, said signal member having the formof a plate Awith a pair of rearwardly bent ears laalong its upper edgewhich are supported upon a horizontal`hing`e pin Il extending betweenthe brackets 9. A torsion spring i2 is coiled around the hinge pin II,with one end bearing against the top edge of the hinged signal member Iand the other against the top of frame 1, thereby exerting a tension ina direction to swing the signal member in a clockwise direction andagainst the pressure exerted thereon through the bellows member 8.

Projecting downwardly fromI the plate-like tportion of the signal memberIIJ is a signal arm I3 which passes through a slot in the top wall I aof the casing I and terminating just below the underside thereof in atransversely arranged target I3a having its upper face preferably coatedwith red paint-or enamel. The target I3a is housed in a separate chamberI4 formed by a shallow web I4a depending from the underside of the topwall I a of the casing and closed by a bottom plate I4b. An aperture I5is formed in thetop wall Ia of the casing in a position to register withthe target I3a in its signalling position, and therefore locatedslightly forward of the target in its normal position, as shown inFigure l.

To complete the indicator assembly, a nipple I6 communicating with thespace enclosed by the bellows 8 and the cup-shaped portion Ia of theframe I supports one end of a short tube II which is inserted into acored passage I8 through the flanged outlet connection a and openingtoward the mouth of the bag 6. In this way, the bellows member respondsto variations in pressure at the bag mouth, expanding axially as thepressure increases beyond a predetermined maximum established by thetension exerted upon the signal member by the torsion spring I2. Thus,when the pressure within the bag reaches a certain maximum, the signalmember is displaced by the bellowsl to bring the target I3a intolposition beneath the aperture, thereby warning Vthe user that the bagshould be emptied.

Now, the device which acts automatically to prevent the functioning ofthe indicator except under conditions of increased pressure due to adirty or clogged dirt bag, is practically a duplication of the elementsconstituting the indicator itself, except that it responds to nozzlesuction and operates a locking finger or detent instead of a signalmember. Thus, there is supported on the under side of the top wall Ia ofthe casing I and at a point forwardly of the indicator mounting, abellows member I9 similar in all respects to the bellows member 8 of thepressure indicator with its open end fitting around an annular webdepending from the under side ofthe top wall Ia. A tube 2I connects theinterior of the bellows I9 with the nozzle chamber, one end of the tubebeing fitted onto a nipple 20a'extending forwardly from the annular web20 and the other end of the tube being fitted onto another nipple 22fastened to the vertical rear wall 2a of the nozzle chamber.

A horizontal lever 23 has pivotal connection with a bracket 24 securedto and depending from the underside of the casing wall Ia intermediatethe pressure indicator mounting and the bellows I9. One end of the leveris connected with the lower end of the bellows I9 by the same type ofbutton and apertureconnection used in the indicator. Between the bellowsand the bracket 24 is a compression spring 25 held in vertical positionbetween the lever and the bottom wall la. This spring acting to opposecontinually the collapse of the bellows member I9 under the suctionproduced in the nozzle chamber.

And finally, extending rearwardly from the pivotal mounting of the lever23 is an arm 26 having an upturned finger or detent 26a which registerswith a slot 21 in the bottom wall of the,

chamber I4 housing the target I3a. This finger has a pointed endnormally positioned below the path of 'the target I3a, preferablyprovided on its under face with a series of teeth or serrations, asclearly shown in Figures 2 and 3.

The Operation of the suction-responsive locking device will be clearlyunderstood from the following discussion: Referring rst to Figure 2, thesuction-actuated bellows member I9 assumes a contracted position when anormal suction is being maintained in the nozzle chamber, as would bethe case when the cleaner is operating upon a carpet of averagethickness. Under these conditions, the spring 25 is not strong enough toovercome the suction and the lever 23 is depressed with the detent 26abelow the path of the target |311, where it can offer no obstruction tothe movement of the signal arm.

However, with the bellows I9 expanded as it would be in case ofdecreased suction within the nozzle chamber, as for instance, when thecleaner is wheeled onto a bare iioor, the compression spring 25 is nowable to overcome the force of the reduced suction with the result thatthe detent 26a is raised either in front of the target I3a, as shown inFigure 1, or into contact with its serrated under-surface, as shown inFigure 3. In the rst instance, theV dirt bag is comparatively clean andtherefore the indicator bellows will be almost entirely collapsed, sothat the target I3a would be well beyond the locking detent. However, itis quite possible that the pressure conditions in the bag would be suchthat the indicator bellows is partially extended, thus carrying thetarget I3a forwardly (as in Figure 2) but not into final signallingposition. In vthis second situation, the lockingdetent would then bedirectly below the target and should the locking device function, theend of the detent Would engage the serrated under-surface of the targetand the locking action would be just as effective. It is important tonote in this connection that the indicator will eventually respond tothe same change in operating conditions that causes thesuction-responsive locking mechanism to operate, and therefore it isessential that the latter should be designed so as to act promptly inorder to move the locking detent into'obstructing position before thesignal arm has .an opportunity to function. For this reason, thesuction-responsive lbellows 'I9 is purposely made largerr than thebellows 8 of the indicator, thus making it relatively more responsive topressure changes and thus insuring its locking action in advance of thefalse action of the indicator. Y

And in conclusion, it may be added that the same result could Ibeobtained by inconporating into the indicator a suction-responsiveKbellows acting directly upon the signal member to compensate for theincreasing pressures due to other than dirt bag conditions. However, anindicator of the so-called vcompensating type is the subject matter of aco-pending application for Letters Patent, bearingSerial No. 283,327 ledJuly 8, 1939. Therefore, it will be understood that the presentdisclosure is directed to the combination with a pressure-responsiveindicator of a separate suction-responsive locking or signalobstructingdevice, and 'having the advantage of being attachable to cleanersalready equipped with a standard type of pressure-responsive lnmosaicodicator or where the use of the locking device may be optional or notentirely necessary.

Having set forth a preferred embodiment of the invention, with theunderstanding that it is not limited to the specific arrangement orcombination of parts herein disclosed,

I claim:

l. The combination with a suction cleaner equipped with an 'indicatorhaving a. signal member responsive to variations in pressure at onepoint in the suction-creating system of the cleaner, oi an auxiliarylocking device adapted to prevent the functioning o said indicatorexcept under predetermined pressure changes and comprising a lockingmember adapted to be shifted into and ont of a position to obstruct themovement or signa-l member of said indicator toward signalling position,and a pressure-responsive element operatively connected with saidshiitable locking member and responsive to pressure variations atanother point in said suction-creating system.

2. The combination with a pressure indicator im: suction cleanerscomprising a shiftable signal member and a pressure-responsiveelementoperatively; connected to said signal member, oi an aniiillar'y lockingdevice adapted to prevent the iinicticnina ci said indicator under predechanges in pressure lcomlitions within suction-creating system of thecleaner and comprising a, locking member .adapted to be shiftinto andout yoi the path of the signal member in its movement into signallingposition, and a pressure-responsive element operatively con neet-eriwith said shitable locking member and, renconsive to tile suctionchanges in said offs- 'liie combination with a bag-pressure indicaterfor a suction cleaner adapted to display a siena?, when a predeterminedincrease in pressure occurs due to a dirty condition of the dirt bag andincluding a pivoted signal member and pressure-responsive bellowsmember, ol.' an auxiliary locking device comprising a lever adapted to-be shifted into and out of the path of movement of said signal membertoward its signalling position, e. bellows member operatively connectedwith said lever arm, the same being relatively larger than the bellowsmember o! vsaid indi'- cator and correspondingly more responsive tovariations in suction at the nozzle of said cleaner, and a. springacting on said lever in a direction to shift the same into obstructingposition, the

tension 'of the spring being adapted to .overcome the force exertedthrough said bellows member upon a predetermined drop in suction at saidnozzle to actuate said lever arm in advance of any response of saidindicator to a correspondlng increase in pressure.

d. The combination with a bag pressure indioator for suction cleaners,comprising e. sbftable signal member and a pressure responsive element,said signal member being ladi'lpted to display a visual signal when apredetermined increase in pressure occurs wit-hin said bag, of anauxiliary locking device for said signal memberv comprising a leverhaving a nger adapted to be shifted into and out of the path of movementci said signal member toward its signaling position, a bellows memberoperatively connected with said lever, and a spring acting on said leverin a direction to shift the same into the path of movement of saidsignal member, the tension of the spring being such as to overcome thefonce exerted on said bellows member upon a predetermined drop insuction at said nozzle and thereby actuate said lever in advance of anyrespouse oi said indicator to a corresponding increase in bag pressurein said bag.

CHARLES G. TRO.

